Refrigerated shipping containers, often known as “reefer containers,” are the backbone of the cold-chain logistics industry. Designed to ship food, clothes, and other things that go bad quickly, they have a high-quality plastic liner for insulation on the inside that keeps the outside temperature from getting in.
In this article, we will break down all there is to know about the insulation of reefer containers.
What is reefer container insulation, and why is it needed?
Insulation in a reefer container is essentially specialised material used to keep the temperature inside a reefer container constant.
When choosing insulation, businesses must think about several things, such as how well it keeps heat in, how much it costs, how easy it is to install, how fragile it is, and how it affects the environment.
There are two main types of insulation used in reefer containers: foam insulation and vacuum insulation panels (VIPs). Foam insulation is less expensive and easier to put in, but vacuum insulation panels are better at keeping heat in and for the environment.
Generally, perishable goods need to be well insulated to keep their quality and freshness during transport. Without insulation, the temperature inside the container can fluctuate, which can cause food to go bad and cause businesses to lose a lot of money.
So, insulation helps to keep the temperature inside the container at a specific level, ensuring that the goods arrive at their destination in excellent condition.
Key factors that impact the insulation performance of reefer containers
There are a number of factors that can affect how well insulation performs in reefer containers, including:
- Ambient temperature: The temperature outside the container can affect the insulation’s ability to maintain a constant temperature inside the container. In extremely hot or cold weather conditions, the insulation must work harder to keep the temperature inside the container consistent.
- Humidity: High levels of humidity can affect the insulation’s thermal performance by reducing its ability to resist heat transfer. This can lead to condensation inside the container, which can damage the goods being transported.
- Wind: Strong winds can cause heat transfer by reducing the effectiveness of the insulation. It can also cause temperature stratification inside the container, where the temperature is warmer at the top and cooler at the bottom.
- Gaps or leaks in the container: Any gaps or leaks in the container can cause heat to enter or escape, leading to temperature fluctuations inside the container. These gaps can be caused by damage to the container or improper sealing of the doors.
- Improper sealing: The doors of the reefer container must be sealed correctly to prevent heat from entering or escaping. If the doors are not sealed correctly, it can cause temperature fluctuations inside the container, leading to spoilage of the goods being transported.
- Insulation damage: Any damage to the insulation can reduce its thermal performance, leading to temperature fluctuations inside the container. The insulation can become damaged due to wear and tear, mishandling of the container, or exposure to extreme weather conditions.
Also read:
What is Offshore Reefer Container Ventilation & Why You Need It
Why Remote Temperature Monitoring is Essential for Offshore Reefer Containers
How are refrigerated shipping containers insulated?
Most reefer containers are insulated with either vacuum insulation panels (VIPs) or foam insulation.
Reefer container insulation material
Foam insulation mainly constitutes a synthetic material known as polyurethane foam. It’s essentially a single-layer form of insulation between two layers of metal sheathing that protects against cooling and heating loss in the event of an accident or misuse.
On the other hand, when making vacuum-insulated panels, a gas-tight shell is placed around a rigid core from which the air has been removed. This allows it to retain heat better than foam insulation.
Reefer container insulation thickness
The thickness of the insulation depends on a number of things, such as the type of insulation used, the outside temperature, the temperature you want inside the container, and the length of the route. Oftentimes, the lower the desired temperature, the thicker the insulation.
For foam insulation, the thickness typically ranges from 60mm to 100mm. For vacuum insulation panels (VIPs), the thickness is usually between 20mm to 30mm. VIPs are more efficient than foam insulation, allowing for thinner insulation while maintaining the same level of thermal performance.
How to optimise insulation performance for reefer containers?
Maintaining the insulation performance of reefer containers is crucial to ensuring that the goods being transported arrive at their destination in excellent condition.
Here are some best practices for optimising the insulation performance of reefer containers:
- Regular inspections and maintenance to identify any issues that may impact its performance.
- Proper handling and storage to prevent damage to the insulation.
- Selecting suitable insulation materials for different types of cargo.
- Pre-cooling the container before loading to help reduce the workload on the insulation during transportation.
- Proper loading of the container to help ensure that the insulation functions correctly during transportation.
Innovative insulation technologies
In recent years, there have been several advancements in reefer container insulation technology that aim to improve the efficiency and performance of insulation.
Some of the latest innovative insulation technologies include:
- Vacuum Insulation Panels (VIPs) are becoming increasingly popular as they can be up to ten times more efficient than traditional insulation materials, allowing for thinner insulation while maintaining the same level of thermal performance.
- Phase Change Materials (PCMs) are a type of material that can absorb and release heat to maintain a constant temperature.
- Microcellular Polyurethane Foam (MCPF) is a type of foam insulation that is lightweight and has a high level of thermal efficiency. This foam consists of small cells that trap air, creating a barrier that prevents heat transfer—making it ideal for shipping.
- Hybrid insulation systems combine different types of insulation materials to create a more efficient insulation system. For example, combining VIP with foam insulation.
Conclusion
Proper insulation is vital for the safe transportation of perishable goods in reefer containers. By choosing the right insulation and conducting regular maintenance, businesses can ensure that their goods arrive at their destination in excellent condition, maintaining their quality and freshness.
Business Director
A graduate (Business) from KDU, Jason Tan, is the current Business Director (Sales) for MGS Icestorm and has been associated with the company for the past 10 years.
With over 13 years in the shipping industry, he has had a significant contribution to Malaysia’s oil and gas industry in the engine and boat supply sector.
His expertise includes managing offshore catering business, offshore reefer containers, AI technology, offshore gas tanks, A60 pressurized cabins, etc. His contributions have helped establish MGS, in partnership (joint venture) with Thermo King and Honeywell to produce state of art Offshore Reefer Container products.